Problem: Solve for $x$ and $y$ using substitution. ${-2x-4y = -2}$ ${x = -3y+2}$
Answer: Since $x$ has already been solved for, substitute $-3y+2$ for $x$ in the first equation. ${-2}{(-3y+2)}{- 4y = -2}$ Simplify and solve for $y$ $6y-4 - 4y = -2$ $2y-4 = -2$ $2y-4{+4} = -2{+4}$ $2y = 2$ $\dfrac{2y}{{2}} = \dfrac{2}{{2}}$ ${y = 1}$ Now that you know ${y = 1}$ , plug it back into $\thinspace {x = -3y+2}\thinspace$ to find $x$ ${x = -3}{(1)}{ + 2}$ $x = -3 + 2$ ${x = -1}$ You can also plug ${y = 1}$ into $\thinspace {-2x-4y = -2}\thinspace$ and get the same answer for $x$ : ${-2x - 4}{(1)}{= -2}$ ${x = -1}$